Polytrimethylene ether glycols can be produced via the acid-catalyzed polycondensation of 1,3-propanediol, optionally in the presence of comonomer diols. Standard methods of producing polytrimethylene ether glycols using acid catalysis are described in U.S. Pat. No. 6,720,459, U.S. Pat. No. 3,326,985, and U.S. Pat. No. 2,520,733.
One standard catalyst is sulfuric acid. However, there are many safety considerations when using sulfuric acid. There is a need for a replacement catalyst that functions as well as or better than sulfuric acid but has none of the safety and environmental drawbacks of sulfuric acid